Beckenring

Beckenring, or pelvic ring, is the ring-shaped bony structure that forms the base of the trunk in humans. It consists of the two hip bones (os coxae), each made up of the ilium, ischium, and pubis, together with the sacrum and coccyx. The hip bones join anteriorly at the pubic symphysis and connect posteriorly to the sacrum at the sacroiliac joints, producing a closed ring that links the axial skeleton to the lower limbs.

Its boundaries and features include the pelvic inlet (the superior opening) and the pelvic outlet (the inferior opening), the acetabula that articulate with the femoral heads, and a network of ligaments that stabilize the ring. The ring encloses the pelvic cavity and supports pelvic organs. Muscles of the pelvic floor and the abdominal wall attach to its surface, contributing to posture and movement.

Functions: It transfers weight from the upper body to the lower limbs, distributes forces during locomotion, protects internal organs, and forms the birth canal in females. The ring's stiffness and integrity are crucial for stability, especially under load or trauma.

Clinical relevance: The pelvic ring is commonly involved in high-energy injuries such as motor vehicle crashes. Pelvic fractures can be stable or unstable and may be associated with major blood loss. Diagnosis relies on radiographs and computed tomography. Treatment ranges from conservative management to surgical stabilization, including external fixation or internal fixation with plates and screws, depending on stability and associated injuries.

Development and variation: The pelvic ring develops from three embryonic structures that fuse into the fused pelvic bones. In adults, sex differences in the pelvis influence the ring's dimensions and shape, particularly the width of the pelvic inlet and outlet, reflecting functional adaptations for childbirth.